Thin-film solar cell modules are composed of a substrate layer on which, in the order listed, a first electrode layer, a semiconductor layer, a second electrode layer, a plastic layer for encapsulating the aforementioned functional layers, and a cover layer are deposited. The plastic layer is directly joined to a circumferential edge region along the substrate layer.
The method can be used, regardless of the material of the functional layers, as long as the substrate layer is transparent to a laser beam used and the first electrode layer is able to absorb the laser beam used.
It is known from the prior art that a laser beam can be used to structure individual or a plurality of functional layers and to perform complete edge deletion by guiding a laser beam, which is absorbed by the layers to be removed, relative to the free surface of the laser-transparent substrate layer and by directing this laser beam at this free surface.
In the method according to the present invention, the use of a laser beam which can be absorbed by the electrode layer is mandatory. This means that manufacturers of solar cell modules, who perform an edge deletion and/or structure at least the first electrode layer by means of a laser, are able to use this laser to carry out the recycling method. Systems in which the beam can be expanded and shaped in a manner suitable to perform edge deletion can also be used to carry out the method according to the present invention.
In contrast to structuring and edge deletion, the objective of which is the complete removal of the layers along the tracks across a width ranging from 20 μm to 90 μm and 10 mm to 60 mm, respectively, without damage to the substrate carrier, it is irrelevant to the recycling method whether or not the substrate carrier is damaged.
Also by comparison, the concern is not the complete removal of one or more layers but only the detachment of the superimposed structure of the functional layers from the substrate layer, with only the first electrode layer being at least partly evaporated and the subsequently following semiconductor layer remaining as unaffected as possible.
At the same time, the local thermal load from the energy input must be kept as low as possible so that the plastic layer does not melt, in order to ensure that the plastic layer and the remaining functional layers continue to adhere to the cover layer, if at all possible, in one piece.